According to well known prior art IC (integrated circuit) packaging methodologies, semiconductor dice are singulated and mounted using epoxy or other conventional means onto respective die attach pads (attach paddles) of a leadframe strip. Traditional QFP (Quad Flat Pack) packages incorporate inner leads which function as lands for wire bonding the semiconductor die bond pads. These inner leads typically require mold locking features to ensure proper positioning of the leadframe strip during subsequent molding to encapsulate the package. The inner leads terminate in outer leads that are bent down to contact a motherboard.
Conventional molding materials are plastic and serve to encapsulate, protect and provide support for the semiconductor dice and wire bonds. While such structures have achieved considerable use, these packages fail to provide shielding which is desirable for certain applications, such as radio frequency (RF) applications. The plastic molding materials are substantially transparent to radio frequency electromagnetic radiation and consequently radio frequency interference signals or electromagnetic interference signals are permitted to enter and escape from the IC package.
With increasing performance and package density demands, the interference signals emitted from IC packages is also increasing. These signals are undesirable as they may interfere with other components or may exceed federally regulated levels.
IC package shield systems and packages including shields have found use in these applications, in order to inhibit the interference signals from entering or exiting the IC package. Conventional shields include a metallic cap which is adhered to a top surface of the IC package. While the incorporation of such a cap is generally effective in shielding the IC package, there is an associated increase in the size of the package, thereby decreasing package density.
It is therefore desirable to provide a shielded integrated circuit package that obviates or mitigates at least some of the disadvantages of the prior art.